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The mechanism of the occurrence of longitudinal surface cracks near slab corner has been investigated based on both the thermal stress analysis of solidifying shell in the continuous casting mold and experimental consideration. In the stress model, the coupling between thermal deformation of the shell and temperature distribution in the mold wall was taken into account. It is cleared that the conventional constant-tapered mold is insufficient to prevent the cracks. By applying a newly developed variable multi-tapered mold, which was designed from the stress analysis, the high-speed castings of 5m/min have been put into practice without corner cracks.

The authors discuss problems related to the bridging method between the asynchronous transfer mode (ATM)-based high-speed multimedia backbone local area network (MBLAN) and a fiber distributed data interface (FDDI), especially the filtering database (FDB) construction method for filtering of frames. The problems are achieving high performance, correspondence to a large-scale system, and prevention of broadcast. The FDB construction method was evaluated based on these problems. Through the evaluation, it was noted that the FDB learning failure rate must be below 10/sup -3/ and a frame filtering process when relaying frames from the MBLAN to an FDDI is not necessary. An FDB access method is proposed. By using a multiple hashing algorithm for the FDB access, the proposed method makes it possible to deal with all terminal addresses, even in a large-scale network system that includes tens of thousands of terminals or more, and also enables high-speed filtering/forwarding of frames between terminals. Both the entry search speed and an effective number of entries in the entry table can be adapted to the requirements of an application by changing the maximum number of hashing times. >